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. Author manuscript; available in PMC: 2015 Feb 20.
Published in final edited form as: Ann Intern Med. 2014 Oct 7;161(7):482–490. doi: 10.7326/M14-0296

Table 1.

U.S. Ambulatory Care Visits Resulting in Cardiac Stress Test Order or Performance, by Demographic and Clinical Characteristics, 1993–2010*

Annual Average, 1993–1995 Annual Average, 2001–2003 Annual Average, 2008–2010




Characteristic Weighted
No. in
Thous.§
Test
Rate
per
10,000
95% CI Weighted
No. in
Thous.§
Test
Rate
per
10,000
95% CI Weighted
No. in
Thous.§
Test
Rate
per
10,000
95% CI P for
trend,
unadj.
P for
trend,
adj.
OR,
trend
aOR,
trend




All visits 1,635 28 (23 to 33) 3,205 42 (35 to 50) 3,805 45 (36 to 53) 0.004 0.134 1.02 1.01
Age, yrs
  18–44 309 12 (7 to 17) 788 29 (18 to 40) 527 19 (12 to 25) 0.012 0.27 1.03 1.02
  45–64 833 50 (38 to 63) 1,594 61 (48 to 74) 1,964 62 (49 to 75) 0.89 0.69 1.00 1.00
  65–79 462 36 (24 to 48) 705 44 (31 to 57) 1,114 62 (44 to 79) 0.013 0.008 1.03 1.04
  >80 67 15 (7 to 24) 111 19 (8 to 29) 174 25 (16 to 34) 0.031 0.143 1.06 1.04
Sex
  Female 820 22 (16 to 28) 1,390 29 (23 to 35) 1,974 37 (29 to 45) 0.003 0.045 1.03 1.02
  Male 815 38 (30 to 47) 1,815 64 (49 to 79) 1,831 58 (45 to 71) 0.078 0.61 1.02 1.01
Race/ethnicity
  Non-Hispanic white 1,218 30 (23 to 37) 2,012 44 (34 to 53) 1,964 44 (34 to 53) 0.056 0.89 1.02 1.00
  Non-Hispanic black 128 25 (10 to 40) 306 54 (26 to 83) 216 30 (15 to 45) 0.20 0.41 1.03 1.02
  Hispanic 77 19 (8 to 30) 209 36 (17 to 54) 305 44 (26 to 63) 0.04 0.141 1.05 1.04
  Other/unknown 211 23 (11 to 36) 678 37 (24 to 49) 1,319 51 (31 to 70) 0.073 0.123 1.03 1.03
Insurance
  Private 742 35 (26 to 44) 2,127 51 (40 to 63) 2,171 49 (38 to 59) 0.186 0.81 1.01 1.00
  Medicare 436 31 (20 to 42) 663 34 (24 to 45) 1,136 48 (35 to 61) 0.016 0.024 1.03 1.03
  Medicaid/Other 421 26 (16 to 35) 287 26 (13 to 39) 404 33 (16 to 50) 0.76 0.46 1.01 1.01
  Uninsured 65 11 (6 to 16) - - (- to -) 86 19 (10 to 28) 0.012 0.058 1.06 1.05
Region
  Northeast 399 29 (16 to 43) 892 53 (34 to 72) 523 32 (20 to 44) 0.80 0.60 1.00 0.99
  Midwest 292 22 (12 to 32) 801 49 (33 to 65) 722 38 (25 to 51) 0.027 0.193 1.03 1.01
  South 503 28 (18 to 39) 926 35 (22 to 48) 1,531 47 (35 to 59) 0.05 0.43
  West 442 32 (22 to 42) 586 36 (23 to 48) 1,029 59 (28 to 90) 0.22 0.21 1.03 1.03
Office/clinic setting
  Urban 1,244 26 (21 to 32) 2,991 46 (37 to 54) 3,555 47 (38 to 57) <0.001 0.027 1.03 1.02
  Rural 391 35 (18 to 52) 214 20 (11 to 29) 269 26 (11 to 41) 0.31 0.126 0.98 0.96
Physician specialty**
  Primary care 806 28 (19 to 38) 1,614 41 (30 to 53) 1,160 28 (20 to 36) 0.93 0.99 1.00 1.00
  Cardiology 617 693 (510 to 876) 1,264 767 (568 to 966) 2,210 1,089 (841 to 1337) 0.006 0.043 1.03 1.03
Reason for visit
  Chest pain 494 572 (408 to 735) 997 912 (605 to 1219) 1,085 1,075 (846 to 1303) 0.004 0.033 1.03 1.02
  Other 1,141 20 (15 to 25) 2,209 29 (23 to 36) 2,721 32 (25 to 40) 0.006 0.40 1.03 1.01
Smoker
  Yes 185 28 (16 to 39) 451 51 (33 to 69) 515 55 (38 to 72) 0.059 0.27 1.03 1.02
  Unknown 474 21 (14 to 28) 828 32 (21 to 43) 1,057 35 (19 to 51) 0.42 0.80 1.01 1.00
  No 1,015 35 (27 to 43) 1,926 46 (37 to 56) 2,233 49 (39 to 59) 0.006 0.051 1.03 1.02
Visit diagnosis
  Hypertension 273 55 (32 to 78) 831 98 (66 to 130) 1,133 107 (75 to 139) 0.006 0.004 1.04 1.04
  Dyslipidemia 141 121 (73 to 169) 397 123 (60 to 186) 620 120 (81 to 159) 0.38 0.74 0.98 0.99
  Diabetes 117 36 (18 to 53) - - (- to -) 253 49 (33 to 65) 0.30 0.51 1.03 1.02
  Obesity 51 62 (31 to 93) - - (- to -) 116 99 (60 to 138) 0.30 0.35 1.03 1.03
Low risk visit
  Yes 802 18 (13 to 23) 1,169 22 (16 to 27) 1,286 21 (15 to 28) 0.50 0.82 1.01 1.00
  No 833 60 (46 to 73) 2,036 94 (74 to 114) 2,519 101 (80 to 121) 0.172 0.009 1.01 1.03

Abbreviations: CI, confidence interval; Avg., average; No., number; CHD, coronary heart disease; Thous., thousands; unadj., unadjusted; adj., adjusted

*

Includes only adults without a diagnosis of CHD. Trend analyses based on logistic regression models using all years of data, with adjustment for patient and provider characteristics. Time intervals exceed 3 years for some subgroups in order to construct reliable confidence intervals.

Cardiac stress test rate among all visits of adults without a diagnosis of CHD and falling within subgroup

§

Total no. of weighted visits resulting in a cardiac stress test order or performance

Time interval extends from 1993–1996 for non-Hispanic black and smoker; 1993–1997 for Hispanic and dyslipidemia; 1993–1998 for age>80 years; 1993–2001 for uninsured, diabetes, and obesity

Time interval extends from 1999–2004 for age>80 years. Data for uninsured, diabetes, and obesity captured in first and third time intervals.

Time interval extends from 2005–2010 for age>80 years; 2007–2010 for rural; 2002–2010 for uninsured, diabetes, and obesity.

Adult visits categorized as low-risk if patient was not a smoker, did not have chest pain, and had no diagnosis for hypertension, dyslipidemia, diabetes, or obesity.

**

Physician specialty available in NAMCS only